Detectives found white powdery substances and a spoon containing a "white crystal-like" residue in the hotel room where the singer Whitney Houston died, according to the final autopsy report.

Houston had cocaine in her system when she died, the report said, and drug paraphernalia, including a rolled up piece of paper, was found in her hotel bathroom.

The report does not specifically identify the substances as cocaine, although the drug was found in toxicology tests in Houston's body. Assistant chief coroner Ed Winter said he could not discuss how recently Houston may have used the drug.

On her final day alive, Houston complained of a sore throat, and an assistant suggested she take a bath before preparing for a pre-Grammy party, according to the report.

The singer died on 11 February after drowning in a bathtub at the Beverly Hilton hotel. Her death has been ruled as accidental and coroner's officials cited heart disease and cocaine use as contributing factors. She died just hours before the party, thrown by her mentor Clive Davis.

Houston was attempting another comeback by starring in a remake of the film Sparkle, in which she plays the mother of three girls who form a singing group and struggle with fame and drug addiction.

A trailer released on Monday featured Houston prominently, including a snippet of her performance of the classic gospel song "His Eye Is on the Sparrow".

Toxicology results also showed Houston had marijuana, Xanax, the muscle relaxant Flexeril, and the allergy medication Benadryl in her system.

The singer also had a build-up of plaque in her arteries that can restrict blood flow. Winter said the condition is common in drug users.

Houston had battled addiction for years, but friends and family had said she appeared committed to making a comeback in the months before her death.

"The biggest devil is me. I'm either my best friend or my worst enemy," Houston told ABC's Diane Sawyer in an infamous 2002 television interview with then husband Bobby Brown.